Disc drives are typical data storage systems. A disc drive includes a rigid housing having a base and a cover that encloses a variety of components. The components include one or more discs having data surfaces that are coated with a magnetizable medium for storage of digital information in a plurality of circular, concentric data tracks. The discs are mounted on a spindle motor that causes the discs to spin and the data surfaces of the discs to pass under respective aerodynamic bearing disc head sliders. The sliders carry magnetic transducers, which write information to and read information from the data surfaces of the discs.
The components also include an actuator mechanism that moves the sliders across the data surfaces of the discs. The actuator mechanism includes a motor, such as a voice coil motor (VCM), a track accessing arm and suspensions that support the sliders. The voice coil motor is operated so as to move the actuator mechanism about an actuator pivot center such that the sliders move from track-to-track across the data surface of a disc.
The base of the disc drive is a complex three-dimensional structure that typically provides a rigid and precise platform upon which multiple mechanical and electronic components, as discussed above, are mounted. Typically, small form factor disc drives include a base made of stamped steel. A stamped steel base can be cost effective and includes a high strength. Stamped steel bases, however, have many limitations. It is difficult to achieve variations in thickness at different portions of the base as well as it being practically impossible to achieve small corner radiuses without machining the base after it has been stamped. In fact, a stamped base design includes through holes where high thickness variation ratios are required. The existence of through holes introduces additional sealing costs and potential leakage problems.
A base includes a variety features for various applications of a disc drive that can not be achieved through pure stamping technology. Typically, force fit components are coupled to a stamped base to satisfy these disc drive application needs. However, forming suitable threads in the base for use in receiving force fit components is difficult. Imperfectly formed threads cause potential leakage problems, corrosion issues on the interface and possible loose fittings between the base and the force fit components. Many times features that should be mounted to the base (such as the breather filter support, carbon filter support, latches, crash stop and etc) are mounted to the top cover to mitigate many of the problems associated with the stamping process. However, mounting such features to the top cover introduces additional disc drive dimensional problems.
The above-mentioned problems associated with stamped steel bases have not posed problems for large disc drives. Normally, large disc drives are made from an aluminum die casting process. However, an aluminum die cast base for small form factor disc drives is not an ideal design for performance and cost reasons. Examples of problems for an aluminum die cast base include low material stiffness and the lack of magnetic properties.
Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.